Is there a specific way, i have to configure the slapd to listem to 636
port..?
And does the 389 search is a secure search...?
Is there a particular way of Starting the TLS operation..?
Thanks in advance

As I already stated. Use "startTLS" with port 389 and it will be secure.
This is all well documented. Please read the slapd(8C) manual page if you
want to understand the options for which port(s) slapd should listen to.

Please read the ldapsearch(1) man page to see the options to ldapsearch
that you can use to require startTLS.